Britain, France, Germany and the US have stressed the need to ensure the safety of nuclear installations threatened by the conflict in Ukraine.
In a phone call on Sunday, the four leaders also reiterated their support for Ukraine against Russia’s invasion.
Moscow and Kyiv have accused each other of shelling a Russian-held nuclear plant, raising fears of a catastrophe.
Meanwhile, President Volodymyr Zelensky urged Ukrainians to be vigilant ahead of Independence Day celebrations.
“Russia could try to do something particularly disgusting, particularly cruel,” he said in a weekend address.
“One of the key objectives of the enemy is to humiliate us,” he added, but “we have to be strong enough to resist all provocation”.
Ukraine’s Independence Day on Wednesday, 24 August, will also mark six months since Russia invaded Ukraine.
The conflict was the subject of a conference call on Sunday bringing together the UK’s Boris Johnson, US President Joe Biden, his French counterpart Emmanuel Macron and German Chancellor Olaf Scholz.
Following its conclusion, they urged military restraint around the Russian-controlled Zaporizhzhia nuclear power station in southern Ukraine, where renewed fighting has led to fears of disaster worse than that in Chernobyl in 1986.
The leaders welcomed a deal – approved by Russian President Vladimir Putin on Friday – to allow UN inspectors to visit the plant at a future date.
The four leaders also said they had “agreed that support for Ukraine in its defence against Russian aggression would be sustained”.
Ukraine reported more missile strikes on Sunday, notably in the town of Nikopol, near the Zaporizhzhia power station.
On Saturday, a fresh drone attack targeted Russia’s Black Sea fleet in the city of Sevastopol in Russian-annexed Crimea. The Russian authorities there said a Ukrainian drone had been shot down.
Agencies